Underreamer



J. D. RUSS UNDERREAMER Filed Jan. 19, 1925 2 Sheets-Sheet 2 iatented @et 23, i923.

narran srarpsy PATENT OFFICE.

- JOHN D. RUSS, OF SPENCER, WEST VIRGINIA, ASSIGNOR F ONE-HALF TO WIRT N,

. RUSS, 0F SPENCER, WEST 'VIRGINIAn UNDERREAMER.

Application led January 19, 1923. Serial No. 613,719.

To @ZZ whom. it may Concern Be it known that l. JOHN D. Ross, residing at SpencerI county of Roane, State of 1lWest Virginia (whose post-office address is Spencer, lV. Va), a citizen of the United States. have invented certain new and useful Improvements in Underreamers, of which the following is a specification.

This invention relates to Well-drilling machinery and, particularly, to devices intended for under-reaming. that is, reaming out or enlarging the well-hole in order to permit the casing to be lowered fart-her down.

ln certain localities in 'this and foreign countries, where the opera-tion of drilling oil, gas7 or artesian wells is carried on,

broken and cavey strata of rock must be drilled through, and these formations are encountered at various depths; Where such a. formation is reached in the usual method of drilling, further attempt to drill the hole deeper in the usual way is useless, due to the caving in of, rock and other substances around the drilling tools, thus retarding the action thereof. A line of casing or pipe must then be put into the wellto afford protection for the tools, in the further effort toy complete the well to the required depth; this can only be accomplished b the alternate use of the drilling tools an an underreamer operating through said line of casing or pipe. I

.en under-reamer of the expansible type comprises a body or stock adapted to be attached to or otherwise carried by the drilling-stem or shaft, and supporting one or more bits or dogs having Cutting edges, the bits being adapted to be compressed or retracted to the internal diameter of the reamer body and to automatically expand or distend as they are passed down through and out of the casing or pipe, and thus present a cutting surface of sutlicient diameter to permit the casing being lowered as the operation of under-reaming proceeds.

My invention has for its basic object to provide an umler-reamer, of the expansible typej which is of simplified construction and which produces improved results, and which` generally stated, comprises a cylindrical stock carrying a pair of radially-movable bit-carrying members associated with means for automatically moving said members radially outward when they pass be'.- neathl the lower end of the casing, in combination with means for automatically locking said members in expanded position during the underrcaming operation.

rEhe invention, in its preferred form, will be better understood by a considerationof the accompanying drawings. forming part of this specification, in connection with the detailed description of the construction and operation hereinafter appearing.

The different views of the under-reamer. shown in the drawings, may be brieiy de-l scribed as follows:

Figure l is a. view in longitudinal section of my under-reamer, the ldrill-stem being shown in elevation; the movable parts carried by the under-reamer stock being` shown 1n the positions which they occupy when the stock is being projected downward in the well-casing and before the bit-carrying members pass beneath the lower end thereof;

Figure 2 is a similar view, showing, however, the movable parts carried by the underreamer stock in the positions which theyv yim ing in the direction of the arrows indicated thereon.

Referring, now, in detail to the drawings:

i designates the under-reamer stock, which, as usual, is cylindrical., as shown, and which is provided with an axial bore 2 intcrsected, toward one end thereof, by a diamctric rectilinear opening 3; with diametrically oppositely disposed slots 4f, 4; and with lubricant-ports 5, 5 extending lonlf itudinally and provided, at one end thereof, with enlarged portions G, 6 closed at the outer ends by screw-caps or plugs 7, 7.

Hl'idably disposed in the opening 3 are a pair of radially movable, bit-carrying members 8, 9, the member 8 being provided with of the stock 1.

i ,emacs i al socket 10, and the member 9 with an ally-projecting stem 11 titting and movin said socket. The stem is provided longitudinal bore 12, receiving a i .anger 13 having an axially projecting m lai, encircling which and bearing at ends against the inner end of said plunand the end wall of said bore 12 is a ed spring 15y functioning to maintain end of the plunger 13 in constant contact with the end wall of the socket 10 in the bit-carrying member 8, and to force said members 8 and 9 away from each other, when said spring is under compresion. Each 'i said members 8 and 9 is provided with .ongitudinally-extending groove 16, re csi-ving the end of a screw 17 threaded into one end of the stock 1, whereby the movent of said members 8 and 9 toward and v -trom each other is limited.

may be here stated thatthe exterior end surfaces of the members 8 and 9 may be formed to provide cutters, in which case the cutters would be integral with the members 8 and 9, or said ends may have secured to them bits or cutters, in any preferred manner.

lach of the members 8 and 9 is provided, diametrically opposite the groove 1G, with a peripheral recess 18, receiving` the toe 19 laterally carried by a lever 20 received in the slot -t and suspended on the pivot pin 21 carried by the stock 1 and provided, to-

ard the end thereof opposite such pivoted end, with an outward-projecting cam portion llach lever 2O is provided, at the pivotal end thereof, with an angular finger 23 projecting into a diametric openingor slot-2e in a mandrel 25 slidable in the bore A coiled spring 26 may be associated with each lever 20, and, as v7n in the drawing, this spring is carried in the stoclr land bears, at one end against the inner longitudinal face l trie lever,`tending to swing the latter outward on its pivot 2l.

" coiled spring 27 is disposed in the bore lthe inner end thereof, and bears, at end, against the end wall of said bore its other end, against the adjacent the mandrel 25, tending to force the l constantly downward.

ration. to insert the stock 1 in the he well-casing A, the levers 20, 20 forced inward from the position thereof .shown in Fig. 2 to the position thereof shown in Fig. 1. and this may be accomished either by forcibly bearing against outer longitudinal faces of said levers f Vhe hands of the operator, or by pulling cord 28, which may be provided. and h. in such case, will be attached to one i of the inamlrel 25, the rope passing ont ough an axial bore 29 in the shaft or stable spindle 30, which is driven from.

.s li

any suitable source of power, as usual. lt will be recognized that. as the levers 20. 20 are forced inward. as indicated. by the hands of the operator, the lever-fingers 23. 23 are rocked upward, these. in turn. forcing the mandrel upward` withdrawingr the lower end of the latter trom between the mem hers 8, 9. Owing to the play of the toes 19 of the levers 2() in the recesses 18.--the levers having a lost-motion connection with said members 8, 9,-the first inward pres- 'sure by the hands of the operator against the levers 20, 2O causes the tingers ot' the levers to force. the mandrel 25 upward to remove the lower end thereof from a position between the members 8, t); thereupon, further pressure against said levers causas the toes 19 to strike the inner end walls ot the recesses 18, 18 in the members 8, 9 and thus force the latter toward each other against the influence of the spring l5. The movable parts are now in the position shown in Fig. 1, which may be called the retracted position of said parts; and the stock 1 may be forced down the wellvcasingA. Now, as soon as the members 9 pass out from the lower end of the well-casing, into the cavity which is formed by jacking up the w'ellwasing, the spring 15 functions to move the members 8. 9 away from each other into what may be called their expanded position; and, as soon as the members 8, 9 separate suiiiciently to permit the plunger or mandrel 25 to pass between them, the spring 27 forces the mandrel 25 downward with its lower end between the members 8, 9.

When it is desired to withdraw the underreamer, the stock 1 is drawn upward in the usual way, and the upper curved cam edges of the projections 22 of the levers 2U, 20 riding into Contact with the lower end `of the well-casing A, said levers are pro`1 gressively forced inward, the tirst move` ment inward of said levers forcing the maridrel 25 upward so that its lower end is removed from between the members 8,I 9, cori# tinued movement of the levers inward cansing the toes 19 of said levers to bear forcibly against the inner end wall of the recesses 18 in the members 8, 9, thereby forcing said members 8, 9 inward or toward each other. `While l have shown and described the spring 2T for forcing the mandrel 25 down` ward, it is to be understood that this spring is not., in fact, essential, and. therefore, may be eliminated, and the force of gravity be depended upon to move the mandrel from the position shown in Fig. 1 to the position shown in Fig. 2, when tl1e"cutter-bearing members 8 and 9 move apart sutiicientlyto permit the mandrel to pass therebetween. lit/'hen the spring 27 is not used. the mandrel 25 should be of' sufficient weight to permit it to drop quickly between the members 8 and 9 when the latterare moved apart.

Having thus fully described my invention, what l claim as new and desire to secure by Letters Patent is:

l. ln an under-reamer, the combination of a tubular stock, a pair of cutter-bearing members slidable diametrically in said stock and adapted to move outward away from each other, so as to project beyond the circumference of said stock, a spring?- pressed mandrel automatically positionab e between said members after outward movement thereof, and lever-connections between said mandrel andl said members and each having a cam projection engageable with the lower end of a well-casing.

2. ln a under-reamer, the combination oic a tubular stock, a pair of cutting-bearing members slidable diametrically in said stock and adapted to move outwardly away from each other, so as to project beyond the circumference of said stock, a mandrel positionable between said members after out ward movement thereof, and lever-connections between said mandrel and members.

3. ln an under-reamer, the combination of a tubular stock, a pair of cutter-bearing members slidable diametrically in said stock and adapted to move outwardly away from each other, so as to project beyond the circumference of seid stock, a slotted mandrel positionable between said members after outward movement thereof, and levers car- .ried by said stock and projecting into the slot of said mandrel and engageable with said members.

4. In an under-reamer, the combination of a tubular stock a pair of cutter-boerin members slidable diametrically in said stesi and adapted to move outward away from each other, so as to project beyond the eircumference of said stock, each of said members having a peripheral recess, a slotted mandrel positionable between said members after outward movement thereof, and levers carried by said stock and projecting into the mandrel-slot and into said recesses of said f members. j

5. In an under-reamer, the combination of a tubular stock, a pair of telescoping, outter-bearing members slidable diametrically in said stock and adapted to move outward away from each other, so as to project beyond the circumference of said stock, spring means for forcing said members outward, and a mandrel automatically positionable between said members after outward movement thereof.

In testimony whereof I hereunto ax my signature.

JOHN D. RUSS. 

